SpringAop 原理及源码 随笔记录

本Markdown编辑器使用[StackEdit][6]修改而来，用它写博客，将会带来全新的体验哦：

• 原理：代理模式
• 源码实现方式1：JdkDynamicAopProxy
• 源码实现2：CglibAopProxy

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原理：代理模式

源码实现方式1：JdkDynamicAopProxy

jdk自带代理模式

@Override    public Object getProxy(ClassLoader classLoader) {        if (logger.isDebugEnabled()) {            logger.debug("Creating JDK dynamic proxy: target source is " + this.advised.getTargetSource());        }        Class<?>[] proxiedInterfaces = AopProxyUtils.completeProxiedInterfaces(this.advised, true);        findDefinedEqualsAndHashCodeMethods(proxiedInterfaces);        return Proxy.newProxyInstance(classLoader, proxiedInterfaces, this);    }... prompt'''

源码实现2：CglibAopProxy

想对于常用代理模式区别在于 将实现接口的方式改为将代理类继承至被代理类。然后进行代理模式其他操作

@Override    public Object getProxy(ClassLoader classLoader) {        if (logger.isDebugEnabled()) {            logger.debug("Creating CGLIB proxy: target source is " + this.advised.getTargetSource());        }        try {            Class<?> rootClass = this.advised.getTargetClass();            Assert.state(rootClass != null, "Target class must be available for creating a CGLIB proxy");            Class<?> proxySuperClass = rootClass;            if (ClassUtils.isCglibProxyClass(rootClass)) {                proxySuperClass = rootClass.getSuperclass();                Class<?>[] additionalInterfaces = rootClass.getInterfaces();                for (Class<?> additionalInterface : additionalInterfaces) {                    this.advised.addInterface(additionalInterface);                }            }            // Validate the class, writing log messages as necessary.            validateClassIfNecessary(proxySuperClass, classLoader);            // Configure CGLIB Enhancer...            Enhancer enhancer = createEnhancer();            if (classLoader != null) {                enhancer.setClassLoader(classLoader);                if (classLoader instanceof SmartClassLoader &&                        ((SmartClassLoader) classLoader).isClassReloadable(proxySuperClass)) {                    enhancer.setUseCache(false);                }            }            enhancer.setSuperclass(proxySuperClass);            enhancer.setInterfaces(AopProxyUtils.completeProxiedInterfaces(this.advised));            enhancer.setNamingPolicy(SpringNamingPolicy.INSTANCE);            enhancer.setStrategy(new ClassLoaderAwareUndeclaredThrowableStrategy(classLoader));            Callback[] callbacks = getCallbacks(rootClass);            Class<?>[] types = new Class<?>[callbacks.length];            for (int x = 0; x < types.length; x++) {                types[x] = callbacks[x].getClass();            }            // fixedInterceptorMap only populated at this point, after getCallbacks call above            enhancer.setCallbackFilter(new ProxyCallbackFilter(                    this.advised.getConfigurationOnlyCopy(), this.fixedInterceptorMap, this.fixedInterceptorOffset));            enhancer.setCallbackTypes(types);            // Generate the proxy class and create a proxy instance.            return createProxyClassAndInstance(enhancer, callbacks);        }        catch (CodeGenerationException ex) {            throw new AopConfigException("Could not generate CGLIB subclass of class [" +                    this.advised.getTargetClass() + "]: " +                    "Common causes of this problem include using a final class or a non-visible class",                    ex);        }        catch (IllegalArgumentException ex) {            throw new AopConfigException("Could not generate CGLIB subclass of class [" +                    this.advised.getTargetClass() + "]: " +                    "Common causes of this problem include using a final class or a non-visible class",                    ex);        }        catch (Exception ex) {            // TargetSource.getTarget() failed            throw new AopConfigException("Unexpected AOP exception", ex);        }    }